The iceberg threat

It is worth using a different perspective to shed some light on the process of situational assessment, and the mental or cognitive processes that lead to SA, to highlight some ever present threats that lie just below the surface of any flight. This can be done by examining the findings from a rapidly growing body of educational research called cognitive load theory (CLT) – which was initially developed at the University of New South Wales in Sydney.

The underlying foundation of CLT concerns the interaction between our limited capacity working memory (or WM) over which we have conscious control and where all mental processing is done, and our unlimited capacity but subconscious long term memory (or LTM).

Long term memory holds all our knowledge in chunks of information. However, only small sections of our long term memory can be accessed through our working memory (hence the term subconscious long term memory). In addition, while experts know more than novices and hence have more information stored in long term memory, they also know it in a qualitatively different way that is more integrated and interconnected, and hence readily available for recall and practical use.

Importantly, it is these integrated and strategically organised schemata – mental structures and frameworks, preconceived ideas, patterns of thought/behaviour – in long term memory that provide us with the organisational scaffold on which to build further knowledge, or in our particular case, a framework we can use to rapidly update our SA according to changing operational conditions.

Without this scaffolding we can still build SA, just like we can build a model without instructions, but it will be a slow and cognitively taxing process that is severely restricted by the limited processing capacity of our working memory as we have to analyse how every piece of new information relates to all other pieces of information.

Put another way, our long term memory can be considered a mental filing system – not only does it hold our knowledge but the way it is organised makes it easier to find what we are looking for, and also tells us where to file incoming “perceived elements in the environment”, according to Dr Endsley. The secretary doing the filing is our working memory and can only be as efficient as the organisation (or lack thereof) of the filing system he or she is accessing. Provided our secretary is suitably motivated he or she will continuously work to reorganise both the individual files and the filing system itself to make its operation more efficient. This continued updating and commensurate improvement in retrieval efficiency, combined with increasing amounts of knowledge stored in the filing system, is the basis of the development of expertise.

As an example to illustrate what this means in terms of SA, imagine being presented with a sequence of simple, seven piece jigsaw puzzles. Seven piece puzzles are chosen as seven is the number of ‘chunks’ of information our working memory can handle at a time when dealing with simple information or with ‘chunks’ recalled from long term memory. (The term chunks is used as our working memory doesn’t differentiate between an individual unit of information or a complete integrated mental structure, or schema, that it imports from our long term memory. This chunking of large amounts of integrated information, rather than having a superior working memory, is how chess experts are able to play multiple games at once.)

The first puzzle we are given comes in a box with the completed picture on it and similarly all the pieces have the usual partial picture on them. In this case the picture on the box provides a scaffold similar to an expert’s strategically organised knowledge held in his long term memory, and similarly the partial pictures on each of the pieces enables you to ‘chunk’ the information contained in their irregular shape, and allows you to ‘place’ each ‘chunk’ in its appropriate location with minimal further thought.

Missing pieces will be obvious, cueing you to go looking for them, as will pieces that don’t belong and should be ignored. To quickly build such a puzzle is easy, as you can hold all seven chunks in your working memory as you slot them into the scaffold provided by the picture on the box. What’s more, you won’t have any difficulty finishing the puzzle even if part of one piece is missing.

This analogy is similar to an expert building and maintaining SA in routine situations that they recognise – that is, situations they have the mental model or ‘picture’ for, and one in which partial, missing and misleading information won’t cause any significant difficulties.
Next, consider what happens if you are given the same seven piece puzzle without the completed picture on the box to guide you. This same puzzle is now more difficult and time consuming, but because we still have pictures on the front of each piece and understand that colours and shapes should line up, we should still be able to complete the puzzle in a reasonable amount of time.

But, imagine how much harder it is in this situation to quickly determine if there are any missing pieces, or pieces from the wrong puzzle – false, missing or misleading information. This represents a novice trying to build their SA – they know what all the individual pieces mean but have difficulty in putting them correctly together, especially under time pressure. For example, the novice might see a rising oil temperature which he recognises goes with an abnormal checklist. The expert, who has a more complete picture, might think of checking if this was confirmed by a falling oil pressure or quantity, whether there was an alternative probe to switch to, is there a maintenance history of higher oil consumption, etc.

Finally, what happens if you are given the same jigsaw puzzle, again with no picture on the box, and this time with no pictures on each piece? Still only seven pieces, but now you have lost any sort of scaffold to build the puzzle with, so you will be down to trial and error – picking up pieces to see if they fit, turning them around, trying again, etc, etc.

This is where your working memory is going to let you down even further, as this time you have to deal with each piece as new information which needs to be analysed or compared to other pieces. Under these more complex operations your working memory capacity will only be able to process two to three units of information at a time.

This last puzzle presents a considerable challenge and would take multiple amounts of time to complete compared to the first example. Moreover, we wouldn’t be able to mentally keep track of where we were up to, what pieces we had tried to fit together, what pieces we had not yet tried. And imagine how difficult it would be to figure out what pieces didn’t belong, if there were any missing pieces, etc.

So returning to the original discussion of the process of situational assessment, and on the basis of the previous examples, imagine what happens if you suddenly find yourself placed in a situation that you don’t recognise, ie a situation that you haven’t been in before or one that you haven’t mentally rehearsed for. Since you are now dealing with new or unfamiliar information, you have no long term memory scaffold to guide your understanding and you will have to use a cognitively taxing guess and check process to build your SA.

Under these conditions the capacity of our working memory drops to two to three units instead of the previous, effectively unlimited amounts of information that depend on what is held in long term memory. You will be constrained because the novelty of the information means you can no longer chunk it and so will have to deal with a far greater number of ‘units’ of information.

The end result is a loss of your ability to quickly make rational decisions, since you won’t understand what is going on around you – that is, you have lost SA. Under these conditions what happens next is anyone’s guess.

Importantly too, this cognitive overload doesn’t slowly build up, but rather occurs in the blink of an eye as processing demands increase at the same time as processing ability decreases. This is why there is a long history in accident and incident reports where highly skilled and professional crews in time critical situations made decisions and took actions that others find difficult to comprehend. They were highly trained and competent professionals but hit the iceberg called OVERLOCR – OVERload Loss of Cognitive Rationality. This iceberg is part of our evolutionary makeup and so can happen to anyone – given the right combination of circumstances.

The object of this article isn’t to offer guidance as to how this unrecognised threat can be managed, nor do space constraints allow it.

However, that said, OVERLOCR is a good reason why immediate reaction to specific EGPWS warnings should be overtrained and mandatory, similarly for go-arounds on unstable approaches or for lack of appropriate configuration below certain heights on approach. Rather, the intent of this article is to explain the hidden iceberg in our cognitive architecture since, to a certain extent, forewarned is forearmed.

Novelty and proximity to the ground where time is limited is a dangerous mix. If you lose SA, by definition you are dealing with novelty, so rebuilding appropriate SA is going to take much longer than the blink of the eye it took to lose it. n

The author would like to thank John Sweller for his conceptual help in developing this article.